1. Field
The present invention is directed to a cassette system having a removable container to be used with a sterilizer. A sealable opening member is associated with the container and operated by an actuating unit and a control circuit during the sterilizing cycle.
2. State of the Art
After medical and dental instruments and other devices are sterilized, they are often stored for a period of time before they are used. After such devices are removed from a sterilizer, they can be easily contaminated. Therefore, some means of protecting the device after sterilization is advantageous.
One method for preserving sterility is to wrap the surgical instrument or other item in towels which are then enclosed in a sheet and taped to create a "wrapped load." During sterilization, however, the wrapping may tend to prohibit complete penetration of the sterilizing steam or gas. Additionally, the wrapping may inhibit complete removal of moisture from the load during a drying phase. Such wrapped loads may also have a limited shelf life, since ambient air may penetrate the wrap.
Certain containers have been devised which remain in an open configuration within a sterilizer (to allow sterilization of devices held within the container), but which close prior to the door of the sterilizer being opened. These containers utilize various meltable fuses or mechanical mechanisms that react to temperature or pressure conditions to seal the load within the container at a particular point in the sterilizing cycle.
For example, U.S. Pat. Nos. 4,251,482 (Sanderson et al.), 4,247,517 (Sanderson et al.), and 4,228,914 (Sanderson), disclose containers with a pressure-responsive valve in a bottom wall. The valve allows steam to circulate within the container while the load is sterilized but then closes in response to conditions in the sterilizer during a vacuum phase. U.S. Pat. Nos. 4,584,182 (Sanderson et al.), 4,558,632 (Sanderson et al.), 4,374,570 (Sanderson et al.), 4,372,921 (Sanderson et al.), and 4,416,417 (Sanderson et al.) disclose containers with a lid held open by a pressure-responsive support mechanism. Some portion of the support mechanism reacts to conditions in the sterilizer to drop the lid onto a lower base portion.
U.S. Pat. Nos. 4,612,872 (Whelchel et al.), 4,349,118 (Sanderson et al.), 4,196,166 (Sanderson et al.) and 4,149,650 (Whelchel et al.) disclose containers in which a closing device has a "fuse" formed of a substance that melts when subjected to certain temperature and pressure conditions. When the fuse melts, the valve shuts thereby to seal the container. U.S. Pat. No. 4,105,407 (Sanderson) discloses a system in which a piston responds to pressure conditions within the sterilizer. The piston acts against a camming device thereby to seal and close the container. The container is closed by means of a sliding lid structure. U.S. Pat. No. 4,050,894 (Genis) discloses a normally solid petroleum product associated with a load-holding capsule. In response to conditions in the sterilizer, the petroleum product liquefies to surround and cover the capsule. The petroleum product subsequently resolidifies to hermetically seal the capsule.
Because such systems respond to temperature and pressure conditions in the sterilizer to actuate the closing or sealing device, they may not be precisely controllable. In addition, once the sealing has taken place, it may not be possible for the container to open itself again for additional sterilizing procedures.
There remains a need for a sterilizer cassette system to effect a sealing of the container at desired times in the sterilizing cycle.